MAJOR POINTS

President Barack Obama on Wednesday:

• Said the U.S. will expand airstrikes to target Islamic State fighters in Syria as well as Iraq.

• Pledged “a steady, relentless effort to take out ISIL wherever they exist using our air power and our support for partner forces on the ground.”

• Stuck by his vow not to send U.S. troops into combat in Syria and Iraq, though Secretary of State John Kerry said separately that troops might be committed to ground operations in Iraq if “something very, very dramatic changes.”

• Announced he will send an additional 450 American troops to assist Iraq in defending itself from the militants, as well as $25 million in aid.

• Called for training and arming selected Syrian opposition groups, with the Saudis providing the training sites, and sought Congress support for that effort.

• Warned that the effort to eradicate the Islamic State will take time — though he did not specify how long — and that in any operation, there are risks to the military members involved.

— From news services

DEVELOPMENTS

• Senate Democratic leaders on Wednesday prepared legislation to expressly authorize the U.S. military to train Syrian rebels. House Republicans, who were to meet this morning to discuss their options, appeared ready to follow their lead.

• The Organization for the Prohibition of Chemical Weapons said Wednesday that it had concluded that a toxic chemical, probably chlorine, was used as a weapon to attack Syrian villages in April. The conclusion, based on months of investigation by a fact-finding team, appeared to indicate that the Syrian government was continuing to use chemical weapons in the country’s civil war, despite having agreed to forswear the weapons, surrender its arsenal and tear down its manufacturing plants.

• Shannon Conley, 19, of Arvada, Colo., pleaded guilty Wednesday in federal court to conspiring to help the Islamic State after she was caught trying to travel to Syria. After meeting an Islamic State member online and becoming engaged to him, she had planned to join him in Syria and fight for the group, if necessary, a plea agreement said. FBI agents arrested her on April 8 at the Denver International Airport before she could board a flight to Turkey.

• France offered Wednesday to take part in airstrikes against extremist fighters in Iraq if needed, but insisted on a more careful tack for Syria. French Foreign Minister Laurent Fabius called for international mobilization against militants from the Islamic State group, which he called “this transnational danger that could reach all the way to our soil.”

• A series of attacks, mainly car bombings targeting security forces and markets, killed at least 30 people Wednesday in Baghdad, authorities said.

— From news services

In a major reversal, President Barack Obama ordered the United States into a broad military campaign Wednesday night to “degrade and ultimately destroy” Islamic State militants, authorizing airstrikes inside Syria for the first time as well as an expansion of strikes in Iraq.

In a prime time televised address to the nation, Obama also announced he was dispatching 450 more U.S. troops to Iraq to assist that country’s besieged security forces. And he called on Congress to authorize a program to train and arm rebels in Syria who are fighting both the Islamic State group and Syrian President Bashar Assad.

Saudi Arabia, a crucial U.S. ally in the Middle East, offered to host the training missions, part of Obama’s effort to persuade other nations to join with the U.S. in confronting the militants.

“This is not our fight alone,” Obama declared. “American power can make a decisive difference, but we cannot do for Iraqis what they must do for themselves, nor can we take the place of Arab partners in securing their region.”

“Our objective is clear: We will degrade and ultimately destroy ISIL through a comprehensive and sustained counterterrorism strategy.”

The president adamantly ruled out the prospect of putting American troops in combat roles on the ground in Iraq or Syria. Even so, Obama’s plans amount to a striking shift for a president who rose to political prominence in part because of his early opposition to the Iraq war.

While in office, he has steadfastly sought to wind down American military campaigns in the Middle East and avoid new wars — particularly in Syria, a country where the chaos of a lengthy civil war has given the Islamic State space to thrive and move freely across the border with Iraq.

Speaking on the eve of the 13th anniversary of the Sept. 11, 2001, attacks, Obama’s plans also amounted to an admission that years of American-led war in the Middle East have not quelled the terror threat emanating from the region.

While administration officials have said they are not aware of a credible threat of a potential attack by the militants in the U.S., they say the Islamic State group poses risks to Americans and interests in the region. Officials are also concerned about the prospect that Westerners, including Americans, who have joined the militant group could return to their home countries to launch attacks.

In recent weeks, the militants have released videos depicting the beheading of two American journalists in Syria. The violent images appear to have had an impact on a formerly war-weary public, with multiple polls in recent days showing that the majority of Americans support airstrikes in both Iraq and Syria.

Obama’s speech was key to his effort to turn around a growing perception that, through inaction, he has allowed the situation there to get out of hand. Republicans, who have vehemently criticized his leadership, gave the address a tepid reception.

“The president has now declared that defeating ISIL is his objective,” said Senate Republican leader Mitch McConnell. “That’s a good start. But Americans don’t want a lecture. They want a plan — a credible, comprehensive plan to deal with this menace that clearly wants to harm us here at home, and that is only becoming stronger by the day.”

The U.S. began launching limited airstrikes against Islamic State targets in Iraq earlier this summer. But officials said Obama was waiting for Iraq to form a new government — a step it took Tuesday — before broadening the effort.

Officials said strikes in Iraq would now be wide-ranging and extend into Syria. Obama plans to proceed with those actions without seeking new authorization from Congress.

Instead, officials said Obama will act under a use of force authorization Congress passed in the days after 9/11 to give President George W. Bush the ability to go after those who perpetrated the terror attacks. Though Obama has previously called for that authorization to be repealed, he has also used the measure as a rationale to take strikes against terror targets in Yemen and Somalia.